scholarly journals A cell-associated oligo-1,6-α-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1

1988 ◽  
Vol 255 (3) ◽  
pp. 865-868 ◽  
Author(s):  
A R Plant ◽  
S Parratt ◽  
R M Daniel ◽  
H W Morgan

Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.

1984 ◽  
Vol 220 (3) ◽  
pp. 811-818 ◽  
Author(s):  
M P Waalkes ◽  
S B Chernoff ◽  
C D Klaassen

Cadmium-binding proteins in the cytosol of testes from untreated rats were separated by Sephadex G-75 gel filtration. Three major testicular metal-binding proteins (TMBP), or groups of proteins, with relative elution volumes of approx. 1.0 (TMBP-1), 1.7 (TMBP-2) and 2.4 (TMBP-3) were separated. Elution of Zn-binding proteins exhibited a similar pattern. TMBP-3 has previously been thought to be metallothionein (MT), and hence this protein was further characterized and compared with hepatic MT isolated from Cd-treated rats. Estimation of Mr by gel filtration indicated a slight difference between MT (Mr 10000) and TMBP-3 (Mr 8000). Two major forms of MT (MT-I and MT-II) and TMBP-3 (TMBP-3 form I and TMBP-3 form II) were obtained after DEAE-Sephadex A-25 anion-exchange chromatography, with the corresponding subfractions being eluted at similar conductances. Non-denaturing polyacrylamide-gel electrophoresis on 7% acrylamide gels indicated that the subfractions of TMBP-3 had similar mobilities to those of the corresponding subfractions of MT. However, SDS (sodium dodecyl sulphate)/12% (w/v)-polyacrylamide-gel electrophoresis resulted in marked differences in migration of the two corresponding forms of MT and TMBP-3. Co-electrophoresis of MT-II and TMBP-3 form II by SDS/polyacrylamide-gel electrophoresis revealed two distinct proteins. Amino acid analysis indicated much lower content of cysteine in the testicular than in the hepatic proteins. TMBP-3 also contained significant amounts of tyrosine, phenylalanine and histidine, whereas MT did not. U.v.-spectral analysis of TMBP-3 showed a much lower A250/A280 ratio than for MT. Thus this major metal-binding protein in testes, which has been assumed to be MT is, in fact, a quite different protein.


1985 ◽  
Vol 31 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Resham S. Bhella ◽  
Illimar Altosaar

Alpha-amylase was purified from the extracellular culture medium of Aspergillus awamori by means of ethanol precipitation. Sephacryl-200 gel filtration and anion-exchange chromatography on Dowex (AG1-X4) resin. The enzyme preparation was found to be homogeneous by means of sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The purified enzyme had a molecular weight of 54 000 ± 2 500 and its isoelectric point was pH 4.2. The enzyme was found to be most active between pH 4.8 and 5.0 and was stable between pH 3.5 and 6.5. The optimal temperature for the enzyme activity was around 50 °C and the enzyme was stable for at least 1 h up to 45 °C retaining more than 80% of its original activity. The Km (37 °C, pH 5.3) for starch hydrolysis was 1.0 g∙L−1 and maltose inhibited the enzyme activity uncompetitively with a K1 value of 20.05 g∙L−1


1998 ◽  
Vol 64 (10) ◽  
pp. 3607-3614 ◽  
Author(s):  
Christine Riou ◽  
Jean-Michel Salmon ◽  
Marie-Jose Vallier ◽  
Ziya Günata ◽  
Pierre Barre

ABSTRACT Aspergillus oryzae was found to secrete two distinct β-glucosidases when it was grown in liquid culture on various substrates. The major form had a molecular mass of 130 kDa and was highly inhibited by glucose. The minor form, which was induced most effectively on quercetin (3,3′,4′,5,7-pentahydroxyflavone)-rich medium, represented no more than 18% of total β-glucosidase activity but exhibited a high tolerance to glucose inhibition. This highly glucose-tolerant β-glucosidase (designated HGT-BG) was purified to homogeneity by ammonium sulfate precipitation, gel filtration, and anion-exchange chromatography. HGT-BG is a monomeric protein with an apparent molecular mass of 43 kDa and a pI of 4.2 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing polyacrylamide gel electrophoresis, respectively. Using p-nitrophenyl-β-d-glucoside as the substrate, we found that the enzyme was optimally active at 50°C and pH 5.0 and had a specific activity of 1,066 μmol min−1mg of protein−1 and a Km of 0.55 mM under these conditions. The enzyme is particularly resistant to inhibition by glucose (Ki , 1.36 M) or glucono-δ-lactone (Ki , 12.5 mM), another powerful β-glucosidase inhibitor present in wine. A comparison of the enzyme activities on various glycosidic substrates indicated that HGT-BG is a broad-specificity type of fungal β-glucosidase. It exhibits exoglucanase activity and hydrolyzes (1→3)- and (1→6)-β-glucosidic linkages most effectively. This enzyme was able to release flavor compounds, such as geraniol, nerol, and linalol, from the corresponding monoterpenyl-β-d-glucosides in a grape must (pH 2.9, 90 g of glucose liter−1). Other flavor precursors (benzyl- and 2-phenylethyl-β-d-glucosides) and prunin (4′,5,7-trihydroxyflavanone-7-glucoside), which contribute to the bitterness of citrus juices, are also substrates of the enzyme. Thus, this novel β-glucosidase is of great potential interest in wine and fruit juice processing because it releases aromatic compounds from flavorless glucosidic precursors.


1980 ◽  
Vol 33 (3) ◽  
pp. 279 ◽  
Author(s):  
RN Murdoch ◽  
Louise E Buxton ◽  
DJ Kay

An improved procedure for the purification of alkaline phosphatase from about 10 g of day 7 pregnant mouse uterine tissue is described. Following homogenization, the procedure involved solubilization and extraction with 0�8% (v/v) Triton X-lOO and 20% (v/v) n-butanol, ammonium sulfate precipitation, concanavalin A-Sepharose 4B affinity chromatography, DEAE-cellulose anion-exchange chromatography and Sephacryl S200 gel filtration. On subjecting 2162-fold purified enzyme preparations to polyacrylamide-gel electrophoresis, a single band of protein coincident with the zone of enzyme activity and having an apparent molecular weight of 205 OOO� lOOOO was identified. Affinity chromatography yielded the largest increase in purity of any step in the procedure and established the glycoprotein nature of the uterine enzyme.


1981 ◽  
Vol 195 (1) ◽  
pp. 159-165 ◽  
Author(s):  
T E Cawston ◽  
W A Galloway ◽  
E Mercer ◽  
G Murphy ◽  
J J Reynolds

1. Rabbit bones in tissue culture synthesize an inhibitor of collagenase during the first 4 days of culture. 2. The inhibitor was purified by a combination of gel filtration, concanavalin A--Sepharose chromatography, ion-exchange chromatography and zinc-chelate affinity chromatography. 3. The purified inhibitor migrated as a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had a mol.wt. of 28000. 4. The inhibitor blocked the activity of the metalloproteinases collagenase, gelatinase, neutral proteinase III (proteoglycanase), human leucocyte collagenase and gelatinase, but not thermolysin or bacterial collagenase. The serine proteinases plasmin and trypsin were not inhibited. 5. The inhibitor interacted with purified rabbit bone collagenase with 1:1 stoichiometry. 6. The inhibitory activity was lost after incubation for 1 h at 90 degrees C, after treatment with trypsin (250 micrograms/ml) at 37 degrees C for 30 min and after reduction and alkylation.


2005 ◽  
Vol 37 (10) ◽  
pp. 702-708 ◽  
Author(s):  
Yan-Hong Li ◽  
Rui Guo ◽  
Qiu-Yu Yin ◽  
Ming Ding ◽  
Si-Liang Zhang ◽  
...  

Abstract Two novel endo-β-1,4-glucanases, EG45 and EG27, were isolated from the gastric juice of mollusca, Ampullaria crossean, by anion exchange, hydrophobic interaction, gel filtration and a second round of anion exchange chromatography. The purified proteins EG45 and EG27 appeared as a single band on sodium dodecylsulfate polyacrylamide gel electrophoresis with a molecular mass of 45 kDa and 27 kDa, respectively. The optimum pH for CMC activity was 5.5 for EG45 and 4.4-4.8 for EG27. The optimum temperature range for EG27 was broad, between 50 °C and 60 °C; for EG45 it was 50 °C. The analysis on the stability of these two endo-β-1,4-glucanases showed that EG27 was acceptably stable at pH 3.0-11.0 even when the incubation time was prolonged to 24 h at 30 °C, whereas EG45 remained relatively stable at pH 5.0-8.0. About 85% of the activity of EG27 could be retained upon incubation at 60 °C for 24 h. However, less than 10% residual activity of EG45 was detected at 50 °C. Among different kinds of substrates, both enzymes showed a high preference for carboxymethyl cellulose. EG45, in particular, showed a carboxymethyl cellulose hydrolytic activity of 146.5 IU/mg protein. Both enzymes showed low activities to xylan (from oat spelt) and Sigmacell 101, and they were inactive to p-nitrophenyl-β-D-cellobioside, salicin and starch.


1974 ◽  
Vol 77 (3) ◽  
pp. 485-497 ◽  
Author(s):  
P. A. Torjesen ◽  
T. Sand ◽  
N. Norman ◽  
O. Trygstad ◽  
I. Foss

ABSTRACT Highly purified human LH, FSH and TSH were isolated from batches of 300 frozen pituitary glands (200 g) by pH, acetone and ethanol fractionation, Sephadex gel filtration, ion-exchange chromatography on DEAE-cellulose and CM-Sephadex, and preparative polyacrylamide-gel electrophoresis. Sodium dodecyl-sulphate (SDS) polyacrylamide gel electrophoresis was used in order to check the purity, the identity and the molecular weight of the purified LH, FSH and TSH. This procedure showed that the hormone preparations consisted of two subunits with molecular weights of: LH: 21 300 and 17 900, FSH: 22 100 and 18 300 and TSH: 20 800 and 16 400. The purity of the hormone preparations was also evaluated by analytical disc electrophoresis at pH 8.9. The purified hormone preparations had radioimmunological activity as follows: LH: 20 000 IU/mg, FSH: 16 500 IU/mg and TSH: 5 IU/mg. All preparations had high biological potency.


1992 ◽  
Vol 38 (9) ◽  
pp. 891-897 ◽  
Author(s):  
Hiroshi Tsujibo ◽  
Yukio Yoshida ◽  
Katsushiro Miyamoto ◽  
Chiaki Imada ◽  
Yoshiro Okami ◽  
...  

Chitinase (EC 3.2.1.14) was isolated from the culture supernatant of a marine bacterium, Alteromonas sp. strain O-7. The enzyme (Chi-A) was purified by anion-exchange chromatography (DEAE-Toyopearl 650 M) and gel filtration (Sephadex G-100). The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular size and pI of Chi-A were 70 kDa and 3.9, respectively. The optimum pH and temperature of Chi-A were 8.0 and 50 °C, respectively. Chi-A was stable in the range of pH 5–10 up to 40 °C. Among the main cations, such as Na+, K+, Mg2+, and Ca2+, contained in seawater, Mg2+ stimulated Chi-A activity. N-Bromosuccinimide and 2-hydroxy-5-nitrobenzyl bromide inhibited Chi-A activity. The amino-terminal 27 amino acid residues of Chi-A were sequenced. This enzyme showed sequence homology with chitinases from terrestrial bacteria such as Serratia marcescens QMB1466 and Bacillus circulons WL-12. Key words: marine bacterium, Alteromonas sp., chitinase.


1998 ◽  
Vol 44 (7) ◽  
pp. 646-651 ◽  
Author(s):  
N Mathivanan ◽  
V Kabilan ◽  
K Murugesan

Chitinase (EC 3.2.1.14) was isolated from the culture filtrate of Fusarium chlamydosporum and purified by ion-exchange chromatography and gel filtration. The molecular mass of purified chitinase was 40 kDa as estimated by sodium dodecyl sulfate – polyacrylamide gel electrophoresis. Chitinase was optimally active at a pH of 5 and stable from pH 4 to 6 and up to 40°C. Among the metals and inhibitors tested, mercuric chloride completely inhibited the enzyme activity. The activity of chitinase was high on colloidal and pure chitin. The purified chitinase inhibited the germination of uredospores of Puccinia arachidis and also lysed the walls of uredospores and germ tubes. The results from these experiments indicated that chitinase of F. chlamydosporum plays an important role in the biocontrol of groundnut rust. Key words: Fusarium chlamydosporum, chitinase, purification, Puccinia arachidis, uredospores.


Sign in / Sign up

Export Citation Format

Share Document